This invention relates in general to a cap for use with containers for fluids, and more particularly involves a screw cap with a liquid supply stopper for use with containers for fluid substances including powders.
In the conventional containers for liquids, such as liquid developers, other liquid chemicals and liquid fuels, an ordinary screw cap is often used during transportation and storage, and when the liquid in the container is used, the screw cap is exchanged with a cap having a liquid supply stopper.
The conventional cap having a liquid supply stopper comprises a cap with a liquid supply opening, and a stopper having a rod passing through the liquid supply opening and projecting out of the opening, the stopper being disposed inside the cap and in pressure contact with the opening when not in use so as to shut the opening tightly by spring means connecting a support member of the rod with a support member fixed inside the cap.
When the liquid in the container is used, the container with the cap having a liquid supply stopper is turned upside down and the projecting rod is pushed against the resilience of the spring means in the cap, for example, by pushing the top of the rod against the bottom of a receiving container so as to space the liquid supply stopper from the liquid supply opening. Thus, the liquid flows out through the liquid supply opening.
Therefore, two different types of caps, namely, an ordinary screw cap and a cap having a liquid supply stopper, are used in the conventional liquid container.
However, the ordinary screw cap is apt to be loosened by vibrations or changes in temperature and atmospheric pressure or the like during storage or transportation, in particular, during air transportation, causing leakage of the liquid.
Moreover, as mentioned previously, when the liquid in the container is used, the screw cap has to be exchanged with the cap having a liquid supply stopper. At that time, unexpected accidents are apt to occur, such as turning over the container, the liquid being scattered by the slightest shock, smearing the clothes of a person who handles the container. In particular, such accidents are very dangerous in case the liquid is corrosive.
In the case of the conventional cap for use with the containers for powders, the above mentioned problems occur likewise.